Composite particle, method of producing same, resin composition containing the particle, reflector formed from the composition, and light-emitting semiconductor device using the reflector

ABSTRACT

A composite particle comprises inorganic compound particles that are derived from inorganic particle and are uniformly dispersed and sintered in a matrix phase composed of silica, or comprises silica particles that are uniformly dispersed and sintered in a matrix phase composed of said inorganic compound particles. The composite particle is prepared by sintering a mixture of (1) finely powdered silica having a BET specific surface area of 50 m 2 /g or greater, (2) an inorganic particle other than silica and (3) water at a temperature of 300° C. or higher to form a glass-like substance, and then crushing the glass-like substance. A spherical composite particle is prepared by melting and spheroidizing the mixture of (1)-(3) in a flame of 1,800° C. or higher. Also provided are a resin composition for a reflector for a light-emitting semiconductor device, a light-emitting semiconductor device that includes said reflector, and a light-emitting semiconductor device in which a light-emitting semiconductor element is encapsulated with said resin composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a reflector for a light-emitting semiconductordevice that exhibits high light reflectance and is resistant to lighttransmission, a resin composition that is ideal for forming thisreflector, and a composite particle that is added to the resincomposition.

2. Description of the Related Art

Conventionally, reflectors for light-emitting semiconductor devices havetypically been formed from compositions prepared by adding a whitefiller material such as titanium oxide, magnesium oxide or zinc oxide,and silica and the like to an epoxy resin or a silicone resin.

However, reflectors formed from a thermoplastic resin or an epoxy resinor the like have a problem in that, when a high-brightness LED or thelike is installed, the resin degrades and yellows due to the effects oftemperature and light (Patent Documents 1 and 2). Further, anotherproblem arises because a large amount of a fine powder of titanium oxideor the like must be used to ensure a white color, and as a result, theflowability of the resin deteriorates, and when the reflector is moldedby transfer or injection molding or the like, molding defects such asincomplete filling and voids tend to occur more frequently (PatentDocument 3).

On the other hand, if a silicone resin is used, absolutely nodiscoloration of the reflector occurs even when a high-brightness LED isinstalled. However, if silica is used as a filler material, then aproblem arises in that some of the emitted light escapes due to similarrefractive index of silica to that of the silicone resin (PatentDocument 4).

CITATION LIST Patent Documents

-   Patent Document 1: JP 2006-140207 A-   Patent Document 2: JP 2008-189833 A-   Patent Document 3: JP 4,778,085 B-   Patent Document 4: JP 2009-221393 A

BRIEF SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a resincomposition which is ideal for a reflector used in a light-emittingsemiconductor device that exhibits high light reflectance and isresistant to light transmission, and to provide a composite particlethat is added to the resin composition.

As a result of intensive investigation based on the above circumstances,the present inventors have found that by using a composite particledescribed below that comprises silica and a white inorganic particlesuch as titanium oxide, a resin composition that is suitable forpreparing a reflector used in a light-emitting semiconductor devicehaving a high light reflectance and a minimal light transmission couldbe obtained, and thus have completed the invention.

In other words, the invention is as described below.

<1> A composite particle prepared by sintering a mixture of (1) finelypowdered silica having a BET specific surface area of 50 m²/g orgreater, (2) an inorganic particle other than silica and (3) water at atemperature of 300° C. or higher to form a glass-like substance, andthen crushing the glass-like substance, wherein said composite particlecomprises inorganic compound particles that are derived from saidinorganic particle and are uniformly dispersed and sintered in a matrixphase composed of silica, or alternatively said composite particlecomprises silica particles that are uniformly dispersed and sintered ina matrix phase composed of said inorganic compound particles derivedfrom said inorganic particles.<2> A spherical composite particle prepared by melting and spheroidizinga mixture of (1) a finely powdered silica having a BET specific surfacearea of 50 m²/g or greater, (2) an inorganic particle other than silicaand (3) water in a flame of 1,800° C. or higher, wherein said sphericalcomposite particle comprises inorganic compound particles that arederived from said inorganic particle and are uniformly dispersed andsintered in a matrix phase composed of silica, or said compositeparticle comprises silica particles that are uniformly dispersed andsintered in a matrix phase composed of said inorganic compound particlesderived from said inorganic particles.<3> A method of producing a composite particle, the method comprising:sintering a mixture of (1) a finely powdered silica having a BETspecific surface area of 50 m²/g or greater, (2) an inorganic particleother than silica and (3) water at a temperature of 300° C. or higher toform a glass-like substance, and then crushing the glass-like substance.<4> A method of producing a spherical composite particle comprisingsilica and an inorganic compound particle derived from said inorganicparticle and integrated with said silica, the method comprising: meltingand spheroidizing a mixture of (1) a finely powdered silica having a BETspecific surface area of 50 m²/g or greater, (2) an inorganic compoundparticle other than silica and (3) water in a flame of 1,800° C. orhigher.<5> A thermosetting resin composition comprising the composite particledescribed in <1> and a thermosetting resin.<6> A thermosetting resin composition comprising the spherical compositeparticle described in <2> and a thermosetting resin.<7> A reflector for a light-emitting semiconductor device, formed fromthe resin composition described in <5>.<8> A reflector for a light-emitting semiconductor device, formed fromthe resin composition described in <6>.<9> A light-emitting semiconductor device in which a light-emittingsemiconductor element is installed on the reflector for a light-emittingsemiconductor device described in <7>.<10> A light-emitting semiconductor device in which a light-emittingsemiconductor element is installed on the reflector for a light-emittingsemiconductor device described in <8>.<11> A light-emitting semiconductor device in which a light-emittingsemiconductor element is encapsulated with the resin compositiondescribed in <5>.<12> A light-emitting semiconductor device in which a light-emittingsemiconductor element is encapsulated with the resin compositiondescribed in <6>.

According to this invention, provided are a resin composition which isideal for a reflector used in a light-emitting semiconductor device thatexhibits high light reflectance and is resistant to light transmission,as well as a composite particle that is added to the composition. Amongcomposite particles, a spheroidized composite particle can be added tothe resin composition in a large amount, and because the refractiveindex of the composite particle can be controlled freely by altering theblend ratio of the inorganic particle relative to silica, problems interms of light loss and light reflection deficiencies can be solved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electron microprobe analyzer (EPMA) mapping diagram of thesilicon (Si) in the composite oxide particle obtained in Example 1A.

FIG. 2 is an electron microprobe analyzer (EPMA) mapping diagram of thetitanium (Ti) in the composite oxide particle obtained in Example 1A.

FIG. 3 is a series of diagrams illustrating a reflector of Example 6,wherein FIG. 3 a illustrates a matrix type concave reflector substrate,FIG. 3 b is a cross-sectional view of a device in which an LED elementhas been installed on an individual reflector substrate, and FIG. 3 c isa plan view of the device shown in FIG. 3 b.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described below in detail.

[(1) Silica]

Representative examples of the finely powdered silica having a BETspecific surface area of 50 m²/g or greater to be used in the inventioninclude dry silica such as fumed silica obtained by spray combustion ofsilicon tetrachloride or a tetraalkoxysilane or the like at hightemperature; precipitated silica obtained by reacting silicontetrachloride or a tetraalkoxysilane with water and performinghydrolysis and condensation; and wet silica such as silica obtained bythe sol-gel method. These finely powdered silica are preferable becausethey have a large surface areas.

Examples of commercially available finely powdered silica having a BETspecific surface area of 50 m²/g or greater typically include fumedsilica, including hydrophilic fumed silica such as Aerosil 90, Aerosil130 and Aerosil 380 (trade names, manufactured by Nippon Aerosil Co.,Ltd.), and hydrophobic fumed silica such as Aerosil R-972, Aerosil R-812and Aerosil R-974 (trade names, manufactured by Nippon Aerosil Co.,Ltd.) which are produced by chemically treating a hydrophilic fumedsilica with an organosilicon compound such as a silane, a silazane or asiloxane. The specific surface area of the silica, which is typicallyreported as a specific surface area measured by the BET adsorptionmethod, is 50 m²/g or greater, and may be as large as 100 to 400 m²/g.Further, the finely powdered silica having a BET specific surface areaof 50 m²/g or greater is also typically referred to as nano silica,which has an average particle size of 0.1 μm (100 nm) or less, and inparticular 0.001 to 0.05 μm (1 to 50 nm).

The average particle size herein can usually be determined as thecumulative weight-average value D₅₀ (or median value) in a particle sizedistribution measurement performed using a laser diffraction method.

[(2) Inorganic Particle Other than Silica]

Examples of the inorganic particle other than silica, that is used bymixing with the finely powdered silica having a BET specific surfacearea of 50 m²/g or greater, include finely powdered oxides, nitrides andthe like. Specific examples of the inorganic particle other than silicainclude oxides such as titanium dioxide, zinc oxide, fumed alumina,magnesium oxide, and zirconium oxide; nitrides such as aluminum nitrideand boron nitride, and the like. The inorganic particle preferably hasan average particle size of 100 nm or less, more preferably 1 to 50 nm.

Examples of the titanium dioxide used herein include fine TiO₂ particleshaving an average particle size of approximately 25 nm, including theproducts sold under trade names CR50, CR80 and R820, that aremanufactured by Ishihara Sangyo Kaisha, Ltd., the products sold undertrade names R62N, GTR100, D918 and R39 that are manufactured by SakaiChemical Industry Co., Ltd., and the product sold under trade nameAeroxide TiO₂ P25 manufactured by Nippon Aerosil Co., Ltd. Both therutile type and anatase type titanium dioxides can be used. Further,examples of the zinc oxide include fine oxide powders having an averageparticle size of 25 nm or 35 nm, such as the products sold under tradenames MZ-306× and MZ-506X that are manufactured by Tayca Corporation. Anexample of a fumed alumina (Al₂O₃) includes the product sold under tradename SpectrAl 100 manufactured by Cabot Corporation.

It is preferable that the compounds described above are mainly used asthe inorganic particle other than the silica, but compounds other thanoxides, such as hydroxides, may also be used in combination with theoxide(s), provided that they do not impair the effects of the invention.

[Composite Particle]

The composite particle of the invention is a composite particle in whichsilica particle is integrated with an inorganic compound particle (thatis derived from the aforementioned inorganic particle used as a rawmaterial), especially a composite particle in which silica particle isintegrated with a metal oxide particle. The aforementioned inorganiccompound particle means a particle of an inorganic compound that isderived from the aforementioned inorganic particle used as a rawmaterial during sintering a mixture of silica, the inorganic particleother than silica, and water at a temperature of 300° C. or higher. Ifthe inorganic particle of the raw material is a nitride, the nitride canbe altered at least partially to an oxide during sintering at atemperature of 300° C. or higher. The composite particle is, dependingon blend ratios of silica and the inorganic particle of the rawmaterial, either a powder of the inorganic compound particles uniformlydispersed and sintered in a matrix phase composed of silica, or is apowder of silica particles that are uniformly dispersed and sintered ina matrix phase composed of said inorganic compound particles. Thecomposite particle generally has the silica (SiO₂) content of 10 to 99%by mass, preferably 20 to 90% by mass, and particularly preferably 30 to80% by mass, and has a content of the inorganic compound particle otherthan silica (particularly metal oxides particle) of 1 to 90% by mass,preferably 20 to 90% by mass, and particularly preferably 30 to 80% bymass. Preferably, the composite particle is a composite oxide particle.

[Method of Producing a Composite Particle]

The production of the composite particle of the invention can beaccomplished by the following methods. For example, a finely powderedsilica and an inorganic particle other than silica are mixed togetheruniformly in a high-speed mixer, and then a liquid such as water isadded slowly until a gel-like substance is obtained. Subsequently, byplacing finely powdered mixture of the gel-like substance in aheat-resistant container such as a ceramic container, and thenperforming a sintering treatment at a high temperature of at least 300°C., preferably 400° C. or higher, and more preferably 600° C. or higher,a uniform sintered product can be obtained. By crushing this sinteredproduct to a fine powder using a crushing device such as a ball mill, asintered composite particle powder containing inorganic compoundparticles uniformly dispersed in a matrix phase of silica (SiO₂), or asintered composite particle powder containing silica (SiO₂) uniformlydispersed in a matrix phase consisting of the inorganic compoundparticle other than silica can be obtained.

[Method of Producing a Spherical Composite Particle]

As aforestated, a method of producing a spherical composite particlecomprises, for example, the steps of preparing a mixture by mixing afinely powdered silica having a BET specific surface area of 50 m²/g orgreater, an inorganic particle other than silica, and water; preparing agel-like substance by sintering the mixture at a temperature of 300° C.or higher; obtaining a composite particle by crushing the glass-likesubstance; and further melting and spheroidizing the composite particlein a flame at a high temperature, generally 1,800° C. or higher.

A simple method of producing a spherical composite particle comprisespreparing a mixture by mixing a finely powdered silica having a BETspecific surface area of 50 m²/g or greater, an inorganic particlesother than the finely powdered silica, and water; preparing anagglomerated powder by removing water from the mixture using spraydrying and the like, and melting and spheroidizing the agglomeratedpowder in a flame at a high temperature, e.g. 1,800° C. or higher. It isnecessary to melt the agglomerated powder in a flame at 1,800° C. orhigher for melting and spheroidization. This temperature is preferably2,000° C. or higher.

The composite particle and spherical composite particle (hereafter alsoreferred to as simply “the composite particle”) of the invention has asilica (SiO₂) content of 10 to 99% by mass, preferably 10 to 90% bymass, and particularly preferably 30 to 80% by mass, and has a contentof an inorganic compound particles other than silica of 1 to 90% bymass, preferably 10 to 80% by mass, and particularly preferably 20 to70% by mass. A silica content of 30 to 80% by mass is particularlydesirable, as it yields a composite oxide having a good stability.

If the silica content is 10% by mass or less, then the binding effectwith an inorganic phase of the other oxide(s), nitride(s) and the likebecomes poor, whereas if the silica content exceeds 99% by mass, thenthe characteristic effects of the composite particle of the inventionmay not be attainable.

In terms of the particle size of the composite particle, when thecomposite particle is used as a filler material for an LED reflectormaterial, the maximum particle size is preferably not more than 150 μm,and the average particle size is preferably from 5 to 30 μm. The maximumparticle size is more preferably not more than 100 μm, and still morepreferably 75 μm or less. The shape of the composite oxide particle ispreferably spherical in terms of enabling a large amount of the particleto be included in the resin, but crushed shapes can also be used withoutany particular problems, provided that they satisfy the particle sizerange described above. Further, a combination of spherical particles andcrushed particles may also be used. The average particle size can bedetermined as the cumulative weight-average value D₅₀ (or median value)in a particle size distribution measurement performed using a laserdiffraction method.

[Resin Composition]

Preferred examples of the resin to which the composite particle of theinvention is added include, in the case where the invention is used as areflector material, thermosetting resins such as epoxy resins, siliconeresins, silicon-epoxy hybrid resins and cyanate resins; andthermoplastic resins such as polyphthalamides. Thermosetting siliconeresins are particularly preferable. The thermosetting silicone resinsinclude an addition-reaction curable silicone resin composition whichincludes a vinyl group-containing polyorganosiloxane and anorganohydrogenpolysiloxanes. The silicone resin composition may alsoinclude additives such as curing catalysts, reaction inhibitors, releaseagents, adhesion aids and coupling agents, according to need.

The amount of the composite particle of the invention to be added to 100parts by mass of the resin described above, is typically from 50 to1,200 parts by mass, and preferably from 100 to 1,000 parts by mass. Ifthe composite particle content is less than 50 parts by mass per 100parts by mass of the resin, then optical properties, e.g. lightreflectance and light transmittance required to use as a reflectormaterial are not obtainable. If the composite particle content exceeds1200 parts by mass, then the spiral flow value and melt viscosityrequired for molding are not obtainable.

When the resin composition of the invention is used as a reflectormaterial, the reflector material may include, besides the aforementionedresin composition of the invention, conventional crystalline silica,fused silica, alumina, zinc oxide, zirconium oxide, glass fiber, carbonfiber, aluminum nitride, magnesium oxide, cristobalite, a coloringmaterial and the like, provided that these other components do notimpair the properties of the reflector.

The aforementioned conventional materials such as titanium oxide,aluminum, zinc oxide or carbon black can be used as a coloring materialfor the reflector. When a composite particle of the invention containingtitanium oxide is used, there is no need to use separately a whitepigment. However, if it is desirable to further increase the whiteness,then additional titanium oxide may be added as a separate component. Theamount of the coloring material to be added is preferably from 0.5 to 20parts by mass relative to 100 parts by mass for the resin.

When the composite particle of the invention is used as a fillermaterial in an encapsulating agent (namely, used in an encapsulatingresin composition) for a light-emitting semiconductor element, thecomposite particle is preferably used in an amount of 0.1 to 500 partsby mass, and preferably 0.5 to 300 parts by mass, relative to 100 partsby mass for the resin such as a transparent silicone resin, epoxy resinor silicone-epoxy hybrid resin.

The resin composition containing the composite particle of the inventionmust be as transparent as possible following curing, and therefore therefractive index of the composite particle is preferably similar to therefractive index of the cured resin. Accordingly, for the compositeparticle used as a filler material in the encapsulating agent, therefractive index is preferably adjusted by altering the proportion ofthe inorganic particles combined with the silica.

For example, when the composite particle is added to a silicone resinhaving a refractive index of approximately 1.53, a crushed and/orspherical finely powdered composite oxide prepared by uniformly mixing100 parts by mass of a finely powdered silica and 100 parts by mass of afinely powdered alumina, and then performing sintering and/or melting ina flame is preferable in terms of the transparency and heat dissipationproperties.

The aforementioned encapsulating resin composition may also include,besides the composite particle of the invention, a phosphor such as YAGand/or finely powdered alumina or silica for the purposes of thixotropycontrol.

An example of the method used for encapsulating the light-emittingsemiconductor element includes a method which comprises dropwise pouringan encapsulating resin composition containing the composite particle ofthe invention, using a discharge device such as a dispenser, into theconcave portion of a reflector having a light-emitting semiconductorelement installed thereon, and then heating the composition at atemperature of 100° C. or greater for approximately 1 to 4 hours to curethe composition and complete the encapsulation.

[Reflector for a Light-Emitting Semiconductor Device]

The reflector for a light-emitting semiconductor device according to theinvention can be produced by molding the resin composition of theinvention on a silver-plated copper lead frame by transfer molding orinjection molding or the like.

[Light-Emitting Semiconductor Device]

A light-emitting semiconductor device of the invention can be obtainedby the method which comprises pouring dropwise the encapsulating resincomposition containing the composite particle of the invention, using adischarge device such as a dispenser, into the concave portion of areflector having a light-emitting semiconductor element installedthereon, and then heating the composition at a temperature of 100° C. orgreater for approximately 1 to 4 hours to cure the composition andcomplete the encapsulation.

EXAMPLES

The invention is specifically described below using a series of examplesand comparative examples, but the invention is in no way limited by theexamples presented below. The raw materials used were as follows.

(1) Hydrophilic fumed silica (SiO₂): manufactured by Nippon Aerosil Co.,Ltd., trade name: Aerosil 380, BET specific surface area: approximately380 m²/g.

(2) Hydrophobic fumed silica (SiO₂): manufactured by Nippon Aerosil Co.,Ltd., trade name: Aerosil R-812, BET specific surface area:approximately 260 m²/g.

(3) Fumed mixed oxides (a physical mixture of silica and alumina,SiO₂/Al₂O₃): manufactured by Nippon Aerosil Co., Ltd., trade name:Aerosil MOX 84.

(4) Hydrophilic fumed metal oxide (TiO₂): manufactured by Nippon AerosilCo., Ltd., trade name: Aeroxide TiO₂ P25.

(5) Hydrophilic fumed alumina (Al₂O₃): manufactured by Nippon AerosilCo., Ltd., trade name: Aeroxide Alu C.

(6) Fumed alumina (Al₂O₃): manufactured by Cabot Corporation, tradename: SpectrAl 100.

(7) Titanium dioxide (TiO₂): manufactured by Ishihara Sangyo Kaisha,Ltd., trade name: CR-60.

Example 1

As shown in Table 1, fumed silica (SiO₂) (Aerosil 380, manufactured byNippon Aerosil Co., Ltd.), titanium dioxide (TiO₂) (CR-60, manufacturedby Ishihara Sangyo Kaisha, Ltd.), fumed alumina (Al₂O₃) (SpectrAl 100manufactured by Cabot Corporation) and water were mixed together using amixing device until a uniform mixture was obtained, thus producing aseries of clay-like mixtures. Each of these mixtures was placed in amuffle furnace at 400° C., 600° C. or 800° C. and heat-treated for 5hours, and was then cooled to room temperature to obtain a sinteredproduct.

TABLE 1 Raw material (units: parts by Example Example Example ExampleComponent mass) 1A 1B 1C 1D (1) Silica 50 70 30 70 (Aerosil 380) (2)CR-60 50 30 20 (TiO₂) SpectrA1 30 40 10 100 (Al₂O₃) (3) Water 10 10 1010 Evaluation results 400° C. Partially insufficient sintered productsexist 600° C. Vitrified 800° C.

Following coarse crushing of the vitrified block produced by baking at800° C. in each of Examples 1A to 1D, crushing was performed using aball mill to produce crushed composite oxide particles (1A to 1D).Analysis of the state of distribution within these powdered particlesrevealed that the aluminum element and the titanium element existed in auniform distribution. The particle size distribution of each of thecrushed particles is shown below in Table 2. The particle sizedistribution was determined on a mass basis using a laser diffractiontype particle size distribution analyzer (Microtrac HRA (X-100)manufactured by Nikkiso Co., Ltd.). The numerical values in Table 2indicate mass % values.

TABLE 2 Example Example Example Example Particle size 1A 1B 1C 1Dgreater than 150 μm 3 4 1 2 100 to 150 μm 12 16 8 5 75 to 100 μm 23 2720 10 50 to 75 μm 35 23 31 20 30 to 50 μm 20 14 21 30 10 to 30 μm 6 1011 21 1 to 10 μm 1 5 7 10 less than 1 μm 0 1 1 2

Comparative Example 1

Fifty parts by mass of fumed silica (SiO₂) (Aerosil 380, manufactured byNippon Aerosil Co., Ltd.), 50 parts by mass of titanium dioxide (TiO₂)(CR-60, manufactured by Ishihara Sangyo Kaisha, Ltd.) and 10 parts bymass of water were mixed together using a mixing device until a uniformmixture was obtained, thus producing a clay-like mixture. This mixturewas placed in a muffle furnace at 200° C. and heat-treated for 5 hours,and was then cooled to room temperature. The obtained product was notsintered at all, and was merely a powder that could easily be broken upby rubbing with hand.

Example 2

Each of the composite oxides obtained by baking at 400° C. in Examples1A to 1D was crushed in a ball mill until a fine powder was obtained,and the crushed powder was then regulated using a sieve to obtain aparticle size of 50 μm or less. Each of these powders was melted bysprinkling onto a flame at 2,000° C., and was then cooled, therebyproducing a series of spherical composite oxides 2A to 2D. Each of thesecomposite oxides was composed of particles having a spherical shape anda uniform composition distribution. The particle size distribution ofeach composite oxide is shown in Table 5. The numerical values in Table5 indicate mass % values. In Example 1A, electron microprobe analyzer(EPMA) mapping diagrams of the silicon (Si) and the titanium (Ti) in thecomposite oxide obtained by baking at 400° C. are shown in FIG. 1 andFIG. 2, respectively.

TABLE 3 Example Example Example Example Particle size 2A 2B 2C 2Dgreater than 100 μm 1 0 1 0 75 to 100 μm 12 8 9 4 50 to 75 μm 20 12 1515 30 to 50 μm 25 35 26 21 10 to 30 μm 20 25 25 30 1 to 10 μm 17 17 2023 less than 1 μm 5 3 4 7

Example 3

Raw materials (mixed fine powders) having a blend ratio shown in Table 4were granulated in the presence of a small amount of water using agranulator. Each of the obtained granular powders was melted bysprinkling onto a flame at 2,000° C., thus producing a series ofspherical composite oxide particles 3A to 3D. The particle sizedistribution of each of the obtained composite particles is shown inTable 5.

TABLE 4 Raw material (units: parts Example Example Example ExampleComponent by mass) 3A 3B 3C 3D (1) Silica 50 70 70 70 (Aerosil 380) (2)Aeroxide 50 20 20 TiO₂ P25 (TiO₂) Aeroxide 30 10 10 Alu C (Al₂O₃) (3)Water 2 2 2 10

TABLE 5 Example Example Example Example Particle size 3A 3B 3C 3Dgreater than 150 μm 1 0 2 0 100 to 150 μm 3 2 5 2 75 to 100 μm 11 14 187 50 to 75 μm 31 34 36 21 30 to 50 μm 21 21 21 30 10 to 30 μm 17 15 1225 1 to 10 μm 11 11 5 12 less than 1 μm 5 3 1 3

(A) Vinyl Group-Containing Organopolysiloxane Synthesis Example 1

One thousand gram of xylene and 5014 g of water were placed in a flask,and a mixture containing 2285 g (10.8 mol) of phenyltrichlorosilane, 326g (2.70 mol) of dimethylvinylchlorosilane and 1478 g of xylene was addeddropwise to the flask. After dropwise addition, stirring was performedfor 3 hours, a waste acid was separated and washing with water wasperformed. After azeotropic dewatering, 6 g (0.15 mol) of KOH was added,and heating for reflux was performed at 150° C. overnight. Twenty sevengram (0.25 mol) of trimethylchlorosilane was added to an obtainedproduct, neutralization with 24.5 g (0.25 mol) of potassium acetate andthen filtration were performed. Subsequently, solvents were distillatedaway under vacuum, and a siloxane resin (A-1) represented by an averageformula (I) shown below was synthesized in the form of a colorless andtransparent solid at room temperature. The vinyl equivalent was 0.0013mol/g, and content of hydroxyl group was 0.01% by mass. The softeningpoint was 65° C.

(C₆H₅SiO_(3/2))_(0.80)((CH₂═CH)(CH₃)₂SiO_(1/2))_(0.20)  (1)

(B) Cross-Linking Agent Having Si—H

An organohydrogenpolysiloxane represented by the structural formulashown below was used as a cross-linking agent.

Hydrogen yield: 0.00377 mol/g

n=2.0 (mean value), X: hydrogen atom, Si—H group equivalent: 0.403.

Hydrogen yield: 0.0076 mol/g

(C) Addition Reaction Catalyst

An octyl alcohol-modified solution containing a chloroplatinic acid(platinum concentration: 2% by mass)

(D) Adhesion Aid

An organohydrogenpolysiloxane represented by the structural formulashown below was used as an adhesion aid.

(wherein, j and k are independently 1, 2 or 3, R is independentlyhydrogen atom, methyl group or isopropyl group, a polystyrene conversionweight-average molecular weight measured by GPC is 3045.)

(E) Reaction Inhibitor 3-methyl-tridecyn-3-ol (F) Release Agent

Rikester EW 440A: manufactured by RIKEN VITAMIN Co., Ltd.

Example 4

Ninety four parts by mass of the vinyl group-containing silicone (A)produced in Synthesis Example 1, 4 parts by mass of the cross-linkingagent (B-1), 17 parts by mass of the cross-linking agent (B-2), 0.1parts by mass of the addition reaction catalyst (C), 6.2 parts by massof the adhesion aid (D), 6.5 parts by mass of the reaction inhibitor(E), 0.7 parts by mass of the release agent (F), and 580 parts by massof the composite oxide (G) produced in Example 3A were subjected topreliminary mixing, and were then kneaded using a continuous kneadingdevice, thus producing a white thermosetting silicone resin composition.

Comparative Example 2

Ninety four parts by mass of the vinyl group-containing silicone (A)produced in Synthesis Example 1, 4 parts by mass of the cross-linkingagent (B-1), 17 parts by mass of the cross-linking agent (B-2), 0.1parts by mass of the addition reaction catalyst (C), 6.2 parts by massof the adhesion aid (D), 6.5 parts by mass of the reaction inhibitor(E), 0.7 parts by mass of the release agent (F), 460 parts by mass of afused spherical silica having an average particle size of 13 μm (G′-1),and 115 parts by mass of titanium dioxide (G′-2) were kneaded using acontinuous kneading device, thus producing a white thermosettingsilicone resin composition.

For each of the compositions of Example 4 and Comparative Example 2, theproperties described below were measured. The results are shown in Table6. Molding was all performed using a transfer molding machine.

<Spiral Flow Value>

Using a molding die prescribed in the EMMI standards, a spiral flowvalue was measured under conditions including a molding temperature of150° C., a molding pressure of 6.9 N/mm², and a molding time of 180seconds.

<Melt Viscosity>

Using a Koka-type flow tester and a nozzle with a diameter of 1 mm, aviscosity at a temperature of 150° C. was measured under a pressure of10 kgf.

<Flexural Strength and Flexural Modulus>

A test piece prepared by using a molding die prescribed in the JIS-K6911standard to perform molding under conditions including a moldingtemperature of 150° C., a molding pressure of 6.9 N/mm² and a moldingtime of 180 seconds, and then post-curing at 150° C. for 4 hours, wasmeasured for flexural strength and flexural modulus at room temperature.

<Light Reflectance and Light Transmittance>

A square-shaped cured product having a length along one side of 50 mmand a thickness of 0.35 mm was prepared under conditions including amolding temperature of 150° C., a molding pressure of 6.9 N/mm² and amolding time of 180 seconds, and the light reflectance and lighttransmittance at 450 nm were measured using an X-rite 8200 manufacturedby S.D.G K.K.

TABLE 6 Comparative Evaluation Unit Example 4 Example 2 Spiral flow Inch35 38 Melt viscosity Pa · s 25 26 Flexural strength MPa 55 56 Flexuralmodulus MPa 7,800 8,400 450 nm light reflectance % 97 94 450 nm light %0.3 2.5 transmittance

From the results in Table 6, it is evident that by using the compositeparticle produced by the invention, the cured product of the resincomposition containing said composite particle can exhibit improvedoptical properties, and particularly light transmittance, whileretaining the other properties such as mechanical strength.

Example 5 CL Molding of Reflector and Physical Properties Thereof

Using the resin compositions produced in Example 4 and ComparativeExample 2, and a totally silver-plated copper lead frame 102, a matrixtype concave reflector 10 illustrated in FIG. 3 was prepared by transfermolding (by molding the encapsulating resin composition to have athickness of 1 mm, a length of 38 mm and a width of 16 mm on top of thesilver surface plated copper substrate) under the following moldingconditions.

The molding conditions were as follows.

Molding temperature: 150° C.

Molding pressure: 70 kg/cm²

Molding time: 3 minutes

Post curing was also performed at 150° C. for 4 hours.

<Warping Measurement>

Warping was measured in two diagonal directions on the resin surfaceside of the post-cured molded reflector having the shape describedabove, and the average of these two values was recorded. The resultsrevealed a warping value of 210 μm for the resin composition produced inExample 4, and a warping value of 560 μm for the resin compositionproduced in Comparative Example 2, confirming that use of the compositeoxide particle of the invention is also effective in yielding superiorwarping properties for the molded products of the resin compositions.

Example 6

A blue LED element 104 was bonded, using a silicone die bonding agent105 (product name: LPS632D, manufactured by Shin-Etsu Chemical Co.,Ltd.), to a portion of the lead frame 102 exposed within the concavebottom of each reflector 100 in the matrix type reflectors 10 moldedusing the resin composition of Example 4 or Comparative Example 2, andthe LED element electrode was connected electrically to another leadportion using a gold wire 103. Subsequently, a silicone encapsulatingagent (LPS380, manufactured by Shin-Etsu Chemical Co., Ltd.) 106 wasinjected into the concave opening in which the LED element 104 had beenpositioned, and curing was performed at 120° C. for 1 hour and then at150° C. for 1 hour to encapsulate the LED element 104.

The matrix type reflector was then divided into individual devices bydicing. Using five of these individual LED devices assembled from areflector produced by molding the resin composition of Example 4 orComparative Example 2, the brightness was measured using a CS-2000Adevice manufactured by Konica Minolta, Inc. When the brightness of theLED which used the reflector molded from the resin composition ofExample 4 was deemed to be 100, the brightness of the LED prepared fromthe resin composition of Comparative example 2 dropped to a value of 93.Further, when the lit LED was observed from the side of the LED package,the device produced using the reflector produced from the resincomposition of Comparative Example 2 exhibited light leakage.

DESCRIPTION OF THE REFERENCE SIGNS

-   10: Concave reflector substrate-   100: Divided individual concave reflector substrate-   101: Resin composition-   102: Lead frame-   103: Gold wire-   104: LED element-   105: Die bonding agent-   106: Transparent encapsulating resin

What is claimed is:
 1. A composite particle prepared by sintering amixture of (1) finely powdered silica having a BET specific surface areaof 50 m²/g or greater, (2) an inorganic particle other than silica and(3) water at a temperature of 300° C. or higher to form a glass-likesubstance, and then crushing the glass-like substance, wherein saidcomposite particle comprises inorganic compound particles that arederived from said inorganic particle and are uniformly dispersed andsintered in a matrix phase composed of silica, or comprises silicaparticles that are uniformly dispersed and sintered in a matrix phasecomposed of said inorganic compound particles derived from saidinorganic particles.
 2. The composite particle according to claim 1,wherein the inorganic particle other than silica is one or moreinorganic materials selected from among metal oxide particle and nitrideparticle with a particle size of 10 μm or less.
 3. The compositeparticle according to claim 2, wherein the inorganic particle other thansilica is one or more inorganic materials selected from among titaniumdioxide, magnesium oxide, zinc oxide, alumina and aluminum nitride.
 4. Aspherical composite particle prepared by melting and spheroidizing amixture of (1) a finely powdered silica having a BET specific surfacearea of 50 m²/g or greater, (2) an inorganic particle other than silicaand (3) water in a flame of 1,800° C. or higher, wherein said sphericalcomposite particle comprises inorganic compound particles that arederived from said inorganic particle and are uniformly dispersed andsintered in a matrix phase composed of silica, or comprises silicaparticles that are uniformly dispersed and sintered in a matrix phasecomposed of said inorganic compound particles derived from saidinorganic particles.
 5. The spherical composite particle according toclaim 4, wherein the spherical composite particle is produced, prior tothe melting in a flame, by sintering the mixture at a temperature of300° C. or higher to form a glass-like substance, and then crushing theglass-like substance.
 6. The composite particle according to claim 4,wherein the inorganic particle other than silica is one or moreinorganic materials selected from among metal oxide particle and nitrideparticle with a particle size of 10 μm or less.
 7. The compositeparticle according to claim 6, wherein the inorganic particle other thansilica is one or more inorganic materials selected from among titaniumdioxide, magnesium oxide, zinc oxide, alumina and aluminum nitride.
 8. Amethod of producing a composite particle, the method comprising:sintering a mixture of (1) a finely powdered silica having a BETspecific surface area of 50 m²/g or greater, (2) an inorganic particleother than silica, and (3) water at a temperature of 300° C. or higherto form a glass-like substance, and then crushing the glass-likesubstance.
 9. A method of producing a spherical composite particlecomprising a silica and an inorganic compound particle derived from aninorganic particle and integrated with said silica, the methodcomprising: melting and spheroidizing a mixture of (1) a finely powderedsilica having a BET specific surface area of 50 m²/g or greater, (2) aninorganic particle other than silica, and (3) water in a flame of 1,800°C. or higher.
 10. The method of producing a spherical composite particleaccording to claim 9, further comprising a step, prior to the meltingand spheroidizing in a flame, of sintering the mixture at a temperatureof 300° C. or higher to form a glass-like substance, and then crushingthe glass-like substance.
 11. A thermosetting resin compositioncomprising the composite particle according to claim 1 and athermosetting resin.
 12. The thermosetting resin composition accordingto claim 11, wherein the thermosetting resin is one or more resinsselected from among epoxy resins, silicone resins, silicone-epoxy hybridresins and cyanate resins.
 13. The thermosetting resin compositionaccording to claim 11, wherein the thermosetting resin composition is awhite resin composition comprising 50 to 1,200 parts by mass of thespherical composite oxide particle (B) per 100 parts by mass of thethermosetting resin (A).
 14. A thermosetting resin compositioncomprising the spherical composite particle according to claim 4 and athermosetting resin.
 15. The thermosetting resin composition accordingto claim 14, wherein the thermosetting resin is one or more resinsselected from among epoxy resins, silicone resins, silicone-epoxy hybridresins and cyanate resins.
 16. The thermosetting resin compositionaccording to claim 14, wherein the thermosetting resin composition is awhite resin composition comprising 50 to 1,200 parts by mass of thespherical composite oxide particle (B) per 100 parts by mass of thethermosetting resin (A).
 17. A reflector for a light-emittingsemiconductor device, formed from the thermosetting resin compositionaccording to claim
 11. 18. A reflector for a light-emittingsemiconductor device, formed from the thermosetting resin compositionaccording to claim
 14. 19. A light-emitting semiconductor device inwhich a light-emitting semiconductor element is installed on thereflector for a light-emitting semiconductor device according to claim17.
 20. A light-emitting semiconductor device in which a light-emittingsemiconductor element is installed on the reflector for a light-emittingsemiconductor device according to claim
 18. 21. A light-emittingsemiconductor device in which a light-emitting semiconductor element isencapsulated with the thermosetting resin composition according to claim11.
 22. A light-emitting semiconductor device in which a light-emittingsemiconductor element is encapsulated with the thermosetting resincomposition according to claim 14.